首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3730篇
  免费   316篇
  国内免费   98篇
耳鼻咽喉   30篇
儿科学   129篇
妇产科学   38篇
基础医学   660篇
口腔科学   53篇
临床医学   247篇
内科学   776篇
皮肤病学   59篇
神经病学   360篇
特种医学   112篇
外国民族医学   1篇
外科学   559篇
综合类   279篇
预防医学   165篇
眼科学   61篇
药学   283篇
中国医学   62篇
肿瘤学   270篇
  2024年   7篇
  2023年   36篇
  2022年   64篇
  2021年   112篇
  2020年   83篇
  2019年   81篇
  2018年   119篇
  2017年   98篇
  2016年   105篇
  2015年   134篇
  2014年   153篇
  2013年   164篇
  2012年   256篇
  2011年   264篇
  2010年   154篇
  2009年   126篇
  2008年   187篇
  2007年   213篇
  2006年   206篇
  2005年   201篇
  2004年   241篇
  2003年   234篇
  2002年   236篇
  2001年   111篇
  2000年   83篇
  1999年   65篇
  1998年   62篇
  1997年   43篇
  1996年   31篇
  1995年   30篇
  1994年   31篇
  1993年   19篇
  1992年   27篇
  1991年   14篇
  1990年   15篇
  1989年   15篇
  1988年   17篇
  1987年   15篇
  1986年   12篇
  1985年   4篇
  1984年   6篇
  1983年   11篇
  1982年   6篇
  1981年   10篇
  1979年   5篇
  1977年   6篇
  1976年   4篇
  1973年   4篇
  1970年   3篇
  1969年   4篇
排序方式: 共有4144条查询结果,搜索用时 31 毫秒
81.
82.
BackgroundHallux valgus (HV) is an important risk factor for falls (in older people); however, the detailed relationship is less understood. We aimed to evaluate postural stability in bilateral HV patients.MethodsTwo groups of 20 female patients—an HV group and a C (i.e., non-HV) group—participated in this study. Evaluations were made using the Timed Up and Go (TUG) test, the Berg Balance Scale (BBS), the Falls Efficacy Scale (FES), track length (LNG), velocity (VEL), enveloped area (ENV), and root mean square area (RMS).ResultsTUG and FES scores were significantly higher and BBS scores were lower in the HV group than in the C group. LNG was significantly longer, VEL was higher, and ENV and RMS were wider in the HV group than in the C group.ConclusionsThe HV group exhibited impaired walking mobility, balance, and postural stability.  相似文献   
83.
Chest radiographs made on 1,007 canine subjects at the University of Pennsylvania Veterinary Hospital between 1965 and 1968 were reviewed to determine whether a relationship between nonspecific chronic canine pulmonary disease and the urban environment could be demonstrated. Radiographs were graded for evidence of chronic pulmonary changes without prior knowledge of the animal’s age or residence. The environment was divided into urban and rural segments based upon the concentration of industrialization in the Philadelphia area and available atmospheric pollution data. No significant differences were noted in the urban-rural distribution of absent, moderate, and severe changes in younger dogs. In middle-aged and older dogs, however, significant differences appeared in the distribution of changes between environmental groups.  相似文献   
84.
85.
86.
Research approaches to biofilm are stratified by a series of analyses: (1) microbial number and species; (2) microbial proteins, such as enzymes; and (3) microbial activity, such as metabolic activity. On the other hand, the hierarchical structure of biology includes the genome, proteome, and metabolome, in which the metabolome is the final output of biological function. Metabolome analysis is the comprehensive analysis of the metabolome, a new strategy for biological research in the 21st century. The stratified structure of biofilm research corresponds to the biological hierarchy, and the analysis of microbial activity, especially metabolic activity, is comparable to metabolome analysis; however, oral biofilm samples are too small to analyze the metabolome by conventional methods. Recently, a new device involving capillary electrophoresis (CE) and time-of-flight mass spectrometry (MS) has been developed, facilitating metabolomic investigation of the central carbon metabolic pathways (i.e., the EMP pathway, pentose phosphate pathway, and TCA cycle) in oral biofilm. Using CE–MS, we analyzed metabolome profiles of oral biofilm after oral rinsing with glucose in vivo and evaluated the effects of oral rinsing with fluoride and xylitol on the metabolome profiles of oral biofilm. The results were somewhat consistent with previous in vitro data obtained from single bacterial strains, namely, Streptococcus and Actinomyces; however, new information describing the metabolic properties of oral biofilm was also obtained. This metabolomic approach will reveal the functional characteristics of oral biofilm in vivo, potentially providing new insights into the nature of oral biofilm in health and disease.  相似文献   
87.
88.
A 66-year-old male was admitted with a two-month history of vomiting and weight loss. Endoscopy showed a pyloric obstruction and the patient underwent subtotal gastrectomy with gastro- jejunostomy. The histopathological study of the specimen revealed primary hypertrophic pyloric stenosis without any evidence of duodenal peptic disease. In the adult, this is a rare cause of gastric outlet obstruction of unknown etiology. It is usually recognized by histopathological examination of the specimen after a gastric resection performed to treat gastric outlet obstruction syndrome. However, some endoscopic and radiological signs, such as the cervix sign, or elongation of the pyloric channel, may give clues about the presence of the disease preoperatively. In symptomatic cases, surgery is the preferred treatment modality.  相似文献   
89.
The aim of the present study was to investigate the relationships between insulin resistance and soluble E-selectin, body mass index (BMI), leptin, and serum lipid profile including triglycerides in nonobese Japanese type 2 diabetic patients. A total of 97 nonobese Japanese type 2 diabetic patients aged 43 to 84 years were examined. The duration of diabetes was 11.2 +/- 0.8 years. In conjunction with BMI and fasting concentrations of plasma glucose, serum lipids (triglycerides, total cholesterol, and high-density lipoprotein cholesterol) and serum insulin, soluble E-selectin, and leptin were also measured. The low-density lipoprotein (LDL) cholesterol level was calculated using the Friedewald formula. Insulin resistance was estimated by the homeostasis model assessment. The subjects were divided into 2 groups according to the value of insulin resistance estimated by the homeostasis model assessment. Values greater than 2.5 were indicative of the insulin-resistant state, and values less than 2.5 were indicative of the insulin-sensitive state. The insulin-resistant group had significantly higher levels of E-selectin, leptin, triglycerides, total and LDL cholesterol, and diastolic blood pressure as compared with the insulin-sensitive group. There was, however, no significant difference in age, sex, diabetes duration, BMI, systolic blood pressure, HbA1c, and high-density lipoprotein cholesterol between the 2 groups. Univariate regression analysis showed that insulin resistance was positively correlated to E-selectin (r = 0.305, P = .003), BMI (r = 0.283, P = .006), leptin (r = 0.296, P = .004), HbA1c (r = 0.241, P = .018), serum triglycerides (r = 0.385, P < .001), serum total (r = 0.240, P = .019) and LDL cholesterol (r = 0.254, P = .013) levels, and systolic (r = 0.247, P = .024) and diastolic (r = 0.305, P = .006) blood pressure. Multiple regression analyses showed that insulin resistance was independently predicted by serum E-selectin (F = 18.4), serum leptin (F = 14.0) and serum triglycerides (F = 20.0) levels, which explained 45.0% of the variability of insulin resistance. From these results, it can be concluded that in conjunction with serum triglycerides and serum leptin, serum E-selectin is another important independent factor associated with insulin resistance in nonobese Japanese type 2 diabetic patients.  相似文献   
90.
The relationship between sphincter of Oddi pressure and the morphological structure of the sphincter was studied in eight dogs prepared with a duodenal cannula. Sphincter of Oddi manometry was performed in awake animals in three directions, ventral, left dorsal, and right dorsal, using a catheter with three radial side holes for recording at one level. The pressure in the ventral direction (26.6 ± 1.06 mmHg) (mean ± SEM) was significantly lower than that in the left and right dorsal directions (30.6 ± 1.42 and 31.2 ± 1.23 mmHg, respectively). This functional manometric difference in the three directions correlated closely with the morphological structure of the sphincter of Oddi; the sum of the thickness of the sphincter of Oddi muscle and duodenal proper muscle was greater on the dorsal than on the ventral side. To our knowledge, this is the first report of axial asymmetry in sphincter of Oddi pressure. (Received May 27, 1997; accepted April 24, 1998)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号